Pterois Volitans and Pterois Miles, both commonly known in the Atlantic Ocean, Caribbean Sea and Gulf of Mexico as lionfish, are a venomous invasive species from the Indo Pacific and the Red Sea. The two visually identical species were introduced into the Atlantic via the US aquarium trade sometime in the early to mid 1980's. Their current invaded range is from North Carolina to South America, including all of the Gulf of Mexico. In less than five years, lionfish have established themselves throughout the Caribbean.
Lionfish may live longer than 15 years and reach sizes exceeding 19 inches in length. They inhabit all types of marine habitats and depths, seen at shorelines and at depths exceeding 1000 feet. Lionfish become sexually mature in less than one year and spawn in pairs. Reproduction occurs throughout the year, about every 4 to 5 days. In the Caribbean, a single female may spawn over 2 million eggs a year. The eggs are held together in a gelatinous mass and are dispersed at the ocean's surface by currents.
Lionfish are carnivores that prey on commercially, recreationally and ecologically important native species, and capable of consuming prey up to half its own body length. Lionfish are voracious predators known to eat native fish and crustaceans in large quantities, including both ecologically and economically important species like grunts, snapper, Nassau grouper, and cleaner shrimp. Studies show that dense lionfish populations can consume more than 460,000 prey fish per acre per year. In heavily invaded sites, they have reduced the native fish population by up to 90% and continue to consume native fish at unsustainable rates.
Due to the absence of natural predators in the invaded areas, lionfish densities have and are growing beyond sustainable levels. The primary means of controlling the lionfish population is through manual collection of the species by divers who target them. Lionfish are edible and in some areas considered a delicacy. Due to the lack of predators, close range capture is feasible. Most divers use a pole spear or a spearing device to capture the lionfish. Some use nets to capture them in protected sanctuaries that do not permit the use of a spearing device. However, due to the presence of the venomous spines on the lionfish and the risk of getting stung, actual physical contact by a diver with the lionfish should be avoided as much as possible.
Once a lionfish is speared, the diver must take caution not to get stung by the up to 18 venomous spines each lionfish possesses. In humans, the lionfish venom can cause intense throbbing, sharp pain, tingling sensations, sweatiness and blistering. In worst case scenarios the symptoms may include headache, nausea, abdominal pain, delirium, seizures, paralysis of limbs, changes in blood pressure, breathing difficulties, heart failure and tremors, pulmonary edema, and loss of consciousness. And therefore, it is important for divers to protect themselves from the spines while removing this invasive species from the reefs.
Throughout the invaded areas, divers use varying types of containment devices ranging from a mesh bag to a 5-gallon water bottle. When using the mesh bag, divers will spear the lionfish first. Then, while the lionfish is on the spear, most divers will cut the venomous spines with a pair of shears prior to inserting the lionfish inside the bag. This manner of containment is time consuming as well as labor intensive for the diver.
Another type of containment used is an adapted 5-gallon water jug. A hole is cut to allow a sliced funnel to be zip-tied to the container. This allows them to insert the lionfish into the container while the lionfish is on the spear, by pressing thru the funnel. The funnel will open while the lionfish is pushed through and close around the spear when the lionfish is fully inserted. When retracting the spear, the lionfish is removed from the spear by the closed funnel. The hard plastic material of the bottle protects the diver from the spines, yet carrying a 5-gallon jug while diving will create an excessive amount of drag, exerting energy from the diver, again time consuming and labor intensive.